Higher Intakes of Antioxidants and Unsaturated Fatty Acid Reduce the Cardiac Autonomic Effects of Particles

Abstract

ISEE-596 Objective: Higher intakes of antioxidants (vitamins C and E, carotene) found in foods such as cruciferous vegetables, and unsaturated fatty acids, including omega-3 from fish and monounsaturated fats from nuts and seeds, may prevent cardiovascular disease. We examined whether higher intake of such antioxidants and fatty acids reduced particle effects on heart rate variability (HRV) in a community-based older population. Materials and Methods: Standard deviation of NN intervals (SDNN), high frequency (HF) and low frequency (LF) components of HRV were measured among 505 older men with 645 total observations between November 2000 and June 2005. PM2.5 was measured at a stationary ambient monitoring site. Dietary intake was evaluated with a self-administered semi-quantitative food frequency questionnaire (FFQ). We used mixed-effects regression models to assess the association between PM2.5 and HRV measures across tertiles of (1) fish and vegetable consumption, and (2) antioxidants and unsaturated fatty acids estimated from the FFQ, controlling for age, BMI, blood pressure, blood glucose, medications, smoking, alcohol intake, total calorie intake, season, and apparent temperature. Results: The effects of 48-hour average of PM2.5 on SDNN, HF, and LF were significantly attenuated across increasing tertiles of vitamin-C and monounsaturated fatty acid (all P-trends <0.05). The responses of SDNN and LF to PM2.5 were also reduced across increasing tertiles of carotene and linolenic acid (omega-6 fatty acid) (all P-trends <0.1). Furthermore, we found effect modification by cruciferous vegetables (P-interaction=0.04) and omega-3 fatty acid (P-interaction=0.08) on SDNN, comparing subjects in the bottom 2 tertiles with those in the top tertile. No effect modification by vitamin-E and α-linolenic acid was observed. Conclusions: Higher intake of antioxidants and unsaturated fatty acids may reduce the autonomic nervous system impacts of particle exposures. This suggests that consumption of fruits, vegetables, nuts, seeds, and fish may modify the cardiovascular response to air pollution.